Drought -- National Drought Mitigation Center


Date of this Version

June 1995


Published in Drought Network News June 1995. Published by the International Drought Information Center and the National Drought Mitigation Center, School of Natural Resources, University of Nebraska – Lincoln.


India is primarily an agricultural country, despite making rapid strides in industrialization in recent decades. The Indian economy is therefore highly dependent on the behavior of the summer monsoon, also known as the southwest monsoon, which occurs during four months (June–September). This accounts for 75% of the annual rainfall over most parts of the country and also generates great demand for rainfall forecasts in different time scales. For nearly a century, Indian meteorologists have been attempting to develop suitable techniques that could be used for preparing long-range forecasts of monsoon rains over India. Walker (1923) has done pioneering work in this field and has introduced the concept of correlation as a measure of interrelationship between preceding events anywhere in the world and subsequent monsoon rainfall over India. Since then, considerable efforts have been made to predict the behavior of monsoons by employing teleconnection signals depicted by the various features of general circulation. During the last seven years, the India Meteorological Department has been issuing forecasts on an all-India basis, accurately using a power regression model based on 16 regional and global parameters, including El Niño (Gowariker et al., 1991). However, these forecasts have seldom been used for precise agricultural planning in any one specific region of the country. The obvious drawback is the uncertainty about the reliability of an all-India forecast for a given meteorological subdivision. Ramana Rao et al. (1994) examined the validity of forecasts for the country as a whole in agricultural planning and management over different meteorological subdivisions. They have also examined the validity of long-range forecasts at the district level in the state of Andhra Pradesh, in southeast India. In this study, we have attempted to examine the behavior of monsoon rainfall in space and time in relation to the El Niño event at the district level in Andhra Pradesh during the years with long-range forecasts of both deficit and normal rainfall on an all-India basis.

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